JPH07117645A - Brake controller - Google Patents

Abstract

PURPOSE:To carry out the ideal brake control even in the retreat of a vehicle, by applying the brake control on the rear and front wheels through the reversal in the retreat of the vehicle, in the control applied on a brake mechanism for the front and rear wheels in the advance of the vehicle. CONSTITUTION:A brake controller is equipped with a target behavior setting means M3 which sets the target behavior of a vehicle on the basis of the result of the detection of a car speed detecting means M1 and a steering angle detecting means M2, and a brake control means M7 controls a brake mechanism M5 on the basis of the sutual vehicle behavior detected by a behavior detecting means M4 and the target behavior. In this case, on the basis of the result of the detection of a retreat judging means M6, i.e., if the actual yaw rate YR> target yaw rate YT, not in retreat, the brake control means M7 applies a brake power to a front outer wheel, and oversteering is eliminated, while if YR<YT the brake control means M7 applies a brake power to a rear inner wheel, and understeering is eliminated, While in retreat, each brake power is applied to the rear outer wheel and the front inner wheel contrary to the above-described control.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a braking control device,
In particular, the present invention relates to a braking control device that individually controls a brake mechanism provided for each wheel to match the vehicle behavior with an ideal state set as a target behavior.

[0002]

2. Description of the Related Art The behavior of a vehicle while it is traveling is greatly affected by the operating conditions of individual brake mechanisms arranged for each wheel. Therefore, in order to ensure stable behavior, it is important to secure an appropriate braking force in each brake mechanism, but it is possible to secure stable behavior by actively controlling the brake mechanism. Is.

From this point of view, conventionally, various braking control devices have been proposed in order to ensure stable vehicle behavior. For example, an anti-lock brake system (ABS) for preventing wheel lock during braking has become widespread in recent years. Has arrived.

Japanese Patent Laid-Open No. 3-276852 discloses that
As a braking control device for the purpose of stabilizing vehicle behavior, it calculates the target yaw rate according to the vehicle speed and steering angle, and generates the braking force only on the inner or outer wheels during cornering to adapt the actual yaw rate to the target yaw rate. Accordingly, an apparatus for eliminating oversteer (excessive cut state) or understeer (short cut state) is disclosed.

When a braking force is generated on the rear inner wheel when the vehicle exhibits understeer, a force in the direction of accelerating turning is generated around the center of gravity of the vehicle to eliminate the understeer, while when the vehicle exhibits oversteer, the front outer wheel is restrained. This is because when power is generated, a force in the turning suppression direction is generated around the center of gravity of the vehicle, and oversteer is eliminated.

[0006]

By the way, the conventional braking control device as described above performs the braking control on the assumption that the vehicle is moving forward. In other words, regarding ABS, in order to ensure stable behavior during forward braking, it is generally
Independent wheel control and rear two-wheel simultaneous low-select control are used.

The front wheels, which are heavily loaded during forward braking,
It is desirable that the left and right wheels behave in the same way in order to generate the maximum braking force by independently performing antilock control on the left and right sides, and to ensure a stable vehicle posture. It controls the brake oil pressure.

In the device disclosed in the above publication, oversteering or understeering is eliminated by generating a braking force on the front outer wheel or the rear inner wheel.
This is because, when the vehicle is moving forward, generating braking force on these wheels is most effective in eliminating oversteering or understeering.

That is, the conventional braking control device does not always perform ideal braking control when the vehicle is moving backward, and has a problem that consideration is not given to maintaining the behavior when the vehicle is moving backward.

The present invention has been made in view of the above-mentioned points, and is provided with a reverse determination means for determining the reverse of the vehicle, and controls the front and rear wheel brake mechanisms to be applied to the front and rear wheels when the vehicle is moving backward. An object of the present invention is to provide a braking control device that solves the above problems by reversing and executing braking control.

[0011]

As shown in FIG. 1, the above object is to achieve a vehicle target based on the vehicle speed detected by the vehicle speed detecting means M1 and the steering angle detected by the steering angle detecting means M2. Target behavior setting means M3 for setting the behavior
In the braking control device that appropriately controls the brake mechanism M5 provided for each wheel so that the setting result of 1 and the detection result of the behavior detection means M4 that detects the actual behavior of the vehicle match, it is determined that the vehicle is moving backward. According to the determination result of the reverse movement determination means M6, the forward control and the backward movement of the vehicle are switched between the control applied to the front wheel braking mechanism M5 and the rear wheel braking mechanism M5 to perform the braking control. And a braking control means M7 for executing the above.

[0012]

In the braking control device according to the present invention, the target behavior setting means M3 sets the target behavior of the vehicle based on the detection result of the vehicle speed detecting means M1 and the detection result of the steering angle detecting means M2. The braking control means M7 controls the brake mechanism M5 based on the actual vehicle behavior detected by the behavior detection means M4 and the target behavior set by the target behavior setting means M3.

At this time, the braking control means M7 controls the brake mechanism M5 based on the determination result of the reverse movement determination means M6 when the vehicle is moving forward and when the vehicle is moving backward. Switch to execute braking control. Therefore, the braking control performed by the braking control means M7 always acts to cause the vehicle to appropriately change its behavior in relation to the traveling direction of the vehicle.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 2 is a block diagram showing the overall construction of a braking control device according to an embodiment of the present invention. In the figure, the brake pedal 1
0 is equipped with a pedal force sensor 11 that detects the pedal force, and is connected to a master cylinder 14 via a booster 12. The master cylinder 14 is a tandem type having two pressurizing chambers, and the hydraulic pressure generated in one pressurizing chamber is transmitted to the brake 20 of the left front wheel 18 and the brake 24 of the right front wheel 22 by the main liquid passage 16. The hydraulic pressure generated in the other pressurizing chamber is transmitted to the brake 30 of the left rear wheel 28 and the brake 34 of the right rear wheel 32 through the main liquid passage 26.

A proportioning bypass valve (hereinafter referred to as P valve) 3 is provided in the middle of the main liquid passages 16 and 26.
6 is provided, and when the hydraulic pressure in the main liquid passage 16 normally rises, the hydraulic pressure in the main liquid passage 26 is reduced when the hydraulic pressure in the main liquid passage 16 is abnormal by a predetermined pressure. When the hydraulic pressure in 16 does not rise normally, the hydraulic pressure in the main liquid passage 26 is not reduced.

When the brake operation is performed while the vehicle is traveling, the front wheels 18, 32
In order to prevent the wheels from being locked while a sufficient load is applied to the wheel 22 and a sufficient braking force is secured as a whole, a relatively high brake pressure is applied to the brakes 20 and 24 of the front wheels 18 and 22 and the rear wheels. This is because it is suitable to supply a relatively low brake pressure to the brakes 30 and 34 of 28 and 32, while there is no room for such pressure reduction when an abnormality occurs in the hydraulic system of the brakes.

Here, the P valve 3 of the main liquid passages 16 and 26
6 downstream, in order to cut the brake oil pressure supplied from the master cylinder 14, cylinder cut valves 40, 4
1 is provided. Further, hydraulic control valves 42, 43 and 44, 45 which are electromagnetic switching valves at three positions are provided in the bifurcated portions of the main liquid passages 16, 26, respectively.

The hydraulic pressure control valves 42 to 45 are provided in the return passage 4
6 is connected to the reservoir 48, and the passages 50 to 53 that bypass the hydraulic pressure control valves 42 to 45 are
Check valves 54 to 57 are provided. The check valves 54 to 57 are one-way valves that allow only the flow of the hydraulic pressure control valves 42 to 45 from the downstream side to the upstream side.

The portions of the main fluid passage 16 between the cylinder cut valve 40 and the hydraulic pressure control valves 42, 44, and the portions of the main fluid passage 26 between the cylinder cut valve 41 and the hydraulic pressure control valves 43, 45 are The accumulator 60 is the accumulator cut valve 6
2, 63 communicate with each other. This accumulator 6
The brake fluid pumped from the reservoir 48 by the pump 64 is stored at high pressure in 0, and when the accumulator cut valves 62 and 63 are opened, the hydraulic pressure control valve 42
Is supplied to the brakes 20, 24, 30, 34 via .about.45. Reference numeral 66 is a relief valve for preventing the generation of excessive brake hydraulic pressure.

These cylinder cut valves 40, 41, hydraulic pressure control valves 42-45, return passage 46, check valves 54-57,
Although the accumulator 60, the accumulator cut valve 62, the pump 64, and the relief valve 66 constitute an ABS actuator that realizes antilock control, the braking control device of the present embodiment realizes a target behavior by using the above-mentioned configuration. The braking control is performed.

The front wheels 18 and 22 are steered wheels, and are steered by a steering device 76 including a steering wheel 70, a steering gear box 72 and the like. Here, the steering angle θ of the steering wheel 70 and the steering torque τ
Are detected by a steering angle sensor 80 and a steering torque sensor 81, which respectively correspond to the steering angle detecting means M2 described above.

Further, when the accelerator pedal 82 is depressed,
The rotation speeds of the wheels 18, 22, 28, 32 detected by the pedal switch 83 forming a part of the backward movement determination means M6 described above correspond to the vehicle speed detection means M1 described above, respectively, and rotation sensors 84, 86, 88. , 90.

Further, the yaw rate sensor 91 corresponding to the behavior detecting means M4 detects the yaw rate of the vehicle,
The front-rear G sensor 92 detects the acceleration G in the front-rear direction of the vehicle, the shift position sensor 93 detects the gear position of the transmission, and the ground vehicle speed sensor 94 detects the absolute vehicle speed with respect to the traveling road. The ground vehicle speed sensor 94 is a known sensor that emits a wave toward the road surface and detects the absolute vehicle speed of the vehicle based on the Doppler shift superimposed on the reflected wave. Sensor 92,
And the shift position sensor 93 together with the shift position sensor 93.

The output signals of the above-mentioned sensors are supplied to the main controller 96, which is the main part of this embodiment and corresponds to the target behavior setting means M3 and the braking control means M7.
The main controller 96 is mainly composed of a computer, and has an input interface 100, an output interface 102, a central processing unit (CPU) 104, and a read only memory (R).
OM) 106, and random access memory (RAM)
It is equipped with 108.

By the way, the braking control system of this embodiment controls the brakes 20, 24, 30, 34 so that the yaw rate actually occurring in the vehicle matches the target yaw rate set according to the running state of the vehicle. Is. Here, the target yaw rate of the vehicle is a function of the vehicle speed V and the steering angle θ as well as a function of the road surface μ, and in performing the calculation, the “road surface μ” is used as a correction coefficient according to the road surface μ.
It is necessary to introduce the concept of the related quantity K ″.

On the other hand, there is a fixed relationship between the road surface μ and the vehicle speed V and the steering torque τ, and the road surface μ can be obtained based on the vehicle speed V and the steering torque τ. For this reason,
In the present embodiment, as described above, the detected value of the steering torque sensor 81 and the rotation sensors 84, 86, 88, 90.
The road surface μ related amount table 1 in which the relationship between τ, V and K is determined so that the road surface μ related amount K can be calculated based on the detected value of
09 is experimentally set and stored in the ROM 106.

Below, the details of the processing executed by the main control device 96 will be explained in detail, and the operation of the braking control device of this embodiment will be explained. Prior to that, each of the brakes 20, 2 will be explained.
The relationship between the braking force generated at 4, 30, and 34 and the yaw rate adopted as the control parameter as the vehicle behavior in this embodiment will be described.

FIG. 3 is a diagram for explaining the effect of a predetermined braking force on the yaw rate during forward turning of the vehicle 120. FIGS. 3A and 3B show the vehicle 120 in an oversteer state. In this case, FIGS. 3C and 3D show the vehicle 1.
20 shows the case where 20 is in the understeer state.

Here, the vehicle 120 is in the oversteer state when the torque in the turning direction around the center of gravity 122 is excessively generated. Therefore, if the torque in the turning direction can be reduced, oversteer can be eliminated and a neutral steer state can be formed. In this case, in order to reduce the torque in the turning direction, it is effective to generate a braking force on the front wheels that are on the outer side during turning as shown in FIG. 3 (B). What has been proposed is as described above.

That is, when a braking force is generated on the right front wheel 22 in the state shown in FIG. 3 (A), a torque in the direction of suppressing the turning acts on the vehicle 120 as a reaction of the braking force. Furthermore, as a result of the frictional force between the wheel and the road surface, which had all acted as centripetal force before the braking force was generated, being dispersed into the braking force and the centripetal force, the cornering force of the right front wheel 22 is reduced and the torque in the turning direction is reduced. Decrease.

As described above, when an appropriate braking force is generated on the right front wheel 22, the braking force generates a correction torque in a direction that suppresses turning, and the vehicle 120 is corrected in the understeer direction. Therefore, when it is executed during oversteer, its behavior is effectively corrected in the neutral steer direction.

On the other hand, when the vehicle 120 is understeered, it is effective to generate a braking force on the rear inner wheel. That is, the vehicle 120 becomes understeer when the torque in the direction for suppressing the turning is excessive as shown in FIG. 3C, and the left rear wheel 28 which is the rear inner wheel as shown in FIG. 3D. When the braking force is generated in the vehicle, the cornering force of the left rear wheel 28 decreases, and the reaction of the braking force generates the correction torque in the turning direction of the vehicle 120, and the understeer is eliminated.

The above-mentioned conventional braking control device utilizes such a principle to realize the target yaw rate set according to the operating condition. By the way, the above-mentioned conventional device is a device that uniformly executes the above-mentioned control regardless of the traveling direction of the vehicle.

Therefore, as shown in FIG.
When 0 is oversteer during backward movement, it is originally effective to generate a braking force on the right rear wheel 28, whereas in the above conventional device, the left front wheel 18, which is the front wheel on the outside of the turn, is applied. Braking force is generated. In this case, although the reaction of the braking force acts in the direction of decreasing the torque in the turning direction, the cornering force of the left front wheel 18 decreases and the turning is promoted, so that the characteristics cannot be effectively corrected.

Similarly, as shown in FIG.
When 0 is understeer during backward movement, it is originally appropriate to generate a braking force on the right front wheel 22, whereas in the above conventional device, the right rear wheel 32, which is the rear wheel on the inside of the turn, is applied. Since the braking force is generated, the cornering force of the right front wheel 32, which is the force in the turning promoting direction, is reduced, and the effective characteristic correction cannot be realized.

In view of the above point, the braking control system of the present embodiment executes the control shown in FIG. 3 when the vehicle 120 moves forward, and when the vehicle moves backward, as shown in FIG. (B), the left rear wheel 28), and the front inner wheel (under Fig. 5 (D), the right front wheel 1) during understeer
8) is characterized in that the content of the braking control is switched according to the traveling direction of the vehicle 120 so as to generate the braking force.

The contents of the processing executed by the main braking device 96 to realize the above functions will be described below with reference to the flowcharts shown in FIGS.

FIG. 6 shows a flowchart of the main routine executed by the main controller 96. When the process shown in the figure is started, first, step 100 (hereinafter referred to as S100)
At, it is determined whether the vehicle is moving backward or moving forward. That is, this step is a step for realizing the above-described backward movement determination means M6.

FIG. 7 shows a flowchart of the backward movement determination routine which is the specific content of S100. That is, FIG. 7 shows the vehicle based on the output signals of the pedal switch 83, the rotation sensors 84, 86, 88, 90, the front and rear G sensor 92, the shift position sensor 93, and the ground vehicle speed sensor 94 provided in the braking control device of the present embodiment. Is a routine for determining whether or not is moving backward.

That is, step S102 is a step of determining whether the shift position is set to the retracted position based on the output signal of the shift position sensor 93. Here, if the shift position is set to the reverse position, it can be determined that the vehicle is moving backward.

Further, S104 is a step for determining whether the output signal of the ground vehicle speed sensor 94 indicates a negative vehicle speed. This is because the ground vehicle speed sensor 94 is a sensor that detects the absolute speed of the vehicle with respect to the traveling road surface, and if the negative absolute speed is detected by this, it can be determined that the vehicle is moving backward.

S106 and S108 are the front and rear G sensor 9
Gs which is the output signal of 2 and any rotation sensor 84,
This is a step of determining whether the vehicle is moving backward based on the calculated value Gw of acceleration obtained by differentiating the output signals of 86, 88 and 90.

That is, the front-rear G sensor 92 for directly detecting the front-rear acceleration generated in the vehicle issues the same sign, for example, a positive output signal Gs during forward-direction acceleration and backward-direction deceleration, and outputs forward-direction deceleration and backward direction. At the time of acceleration, both emit a sign opposite to that, for example, a negative output signal Gs. On the other hand, the differential value Gw of the output signals of the rotation sensors 84, 86, 88, 90 emits a positive sign if the rotation speed of the wheel is fast regardless of forward or reverse, and a negative sign if the rotation speed decreases.

Therefore, when the vehicle is moving forward, Gs and Gw have the same sign according to the acceleration / deceleration, but when the vehicle is moving backward, they have opposite signs. . At S108, the backward determination is performed by paying attention to such characteristics, and at S106, the rotation sensors 84, 86,
Gw and Gs obtained by differentiating the output signals of 88 and 90 are multiplied, and when the result is negative, it is determined that the vehicle is moving backward.

Steps S110 and S112 are steps for making a vehicle reverse determination based on the operation state of the accelerator pedal 82 and the detected value Gs of the front and rear G sensors. That is, in S110, it is determined from the output state of the pedal switch 83 whether the accelerator pedal 82 is depressed. If the accelerator pedal 82 is depressed here, the vehicle should accelerate in the forward direction or the backward direction.

If the vehicle is accelerating in the reverse direction, the front-rear G sensor 92 should detect a negative acceleration, and the condition of S112 is satisfied, while the vehicle is accelerating in the forward direction. If so, the condition of S112 is not satisfied. Therefore, it is possible to determine the backward movement of the vehicle by executing the processing of S110 and S112.

In the present embodiment, the backward movement determination of the vehicle is executed by performing the above processing, and the above S10 is executed.
If the conditions are satisfied in S2, S104, S108, and S112, the process proceeds to S114, it is determined that the vehicle is in the backward movement, and the backward movement determination routine shown in FIG. 7 is ended. The above 4
Species determination does not necessarily require all,
The configuration may be such that one or more types of determination are appropriately and selectively performed as needed.

When the backward determination is completed in this way, the routine of FIG. 6 is continued again. Then, when it is determined that the vehicle is not moving backward, that is, the vehicle is moving forward, the braking control device of the present embodiment proceeds to S200 to realize the processing shown in FIG. 3, while the vehicle is moving backward. If it is determined that there is, S60 for executing the processing shown in FIG.
Go to 0.

S200 is a step of determining whether the vehicle is in the oversteer state. Before executing this step, the main controller 96 executes the yaw rate calculation routine shown in FIG. 8 to calculate the target yaw rate Y _R according to the vehicle speed and the steering angle, and also to realize the actual vehicle. The process of reading the actual yaw rate Y _T that has occurred is performed. Then, in this step, Y _R and Y _T are compared with each other to determine whether oversteering occurs.

The processing contents of the yaw rate calculation routine shown in FIG. 8 will be described below. When the routine shown in FIG. 8 is started, first, in S202, the rotation sensors 84, 8
The vehicle speed V is calculated based on the pulse signals from 6, 88 and 90. In this sense, this step is a step for realizing the vehicle speed detection means M1 described above. In the present embodiment, by calculating the vehicle speed V using the pulse signal from the rotation sensors 84, 86, 88, 90 which represents the second highest speed, wheel slip, lock, etc. Highly accurate vehicle speed calculation is possible by eliminating the influence.

Then, in S204, the steering angle sensor 8
The steering angle θ is read from 0, and the steering torque τ is read from the steering torque sensor 81 in S206. Then, in S208, the road surface μ related amount table 109 is searched with the vehicle speed V and the steering torque τ to determine the road surface μ related amount K corresponding to the traveling road surface.

Then, in S210, using the vehicle speed V, the steering angle θ, and the road surface μ-related amount K described above, the target yaw rate Y _T that would occur if neutral steering is realized in the current running state is calculated as follows. Calculate according to the formula. However, in the following equation, R indicates a steering gear ratio and L indicates a wheel base.

Y _T = V · sin (θ / R) · K / L (1) When the target yaw rate Y _T is obtained as described above, the process proceeds to S212, in which the output signal of the yaw rate sensor 91 is output. Further, the actual yaw rate Y _R is read and the routine shown in FIG. 8 ends.

The above-described S200 shown in FIG. 6 is a step of comparing the target yaw rate Y _T thus obtained with the actual yaw rate Y _R , and when Y _R > Y _T , Y _R
It is appropriate to add a correction in the direction of decreasing. Therefore, in the present embodiment, if the above condition is satisfied in S200, the process proceeds to S300 and the process of adding the braking force to the front outer wheel is performed.

More specifically, first, the turning direction of the vehicle is determined based on the output signal of the steering angle sensor 80, and the left and right front wheels 18 and 22 are selected as the outer wheels when turning.
Then, for example, when the right front wheel 22 is applicable as shown in FIG. 3B, the cylinder cut valve 40 is closed and the accumulator cut valve 62 is supplied so that the brake hydraulic pressure is supplied only to the brake 24 provided on the right front wheel 22. With opening
Processing for opening the hydraulic control valve 44 is performed.

In this case, the torque in the turning direction around the center of gravity of the vehicle is reduced as described above, and the oversteer characteristic is appropriately eliminated.

On the other hand, in S200, Y_R> Y_TBut
If not established, proceed to S400 and go to Y_R<Y_TSuccess
Determine the rightness. This condition holds true
To Y _RIs too small, that is, in the case of understeer
Therefore, to correct this, apply braking force to the rear inner wheel.
Appropriate addition is as described above.

Therefore, if it is determined in S400 that the condition is satisfied, the process proceeds to S500, in which a process for generating an appropriate braking force on the rear inner wheel is executed, and the current process is terminated. Note that the rear inner wheel can be selected based on the output signal of the steering angle sensor 80 as in the case of S300 above. Then, for example, when the left rear wheel 28 corresponds to the cylinder cut valve 4 as shown in FIG.
By closing 1 and opening the accumulator cut valve 63, and by opening the hydraulic control valve 43 appropriately, an appropriate braking force can be generated.

On the other hand, when it is determined in S100 that the vehicle is moving backward and the processing in S600 and thereafter is executed, the braking control executed in S100 to S500 and the processing in which the front and rear wheels are reversed are executed.

That is, if the oversteer characteristic appears when the vehicle is moving backward, it is determined in S600 that Y _R > Y _T is satisfied. Thereafter, in S700, a braking force is applied to one of the rear wheels 28 and 32 that corresponds to the outer wheel in the turning direction. Execute the process. Further, when the understeer characteristic appears when the vehicle moves backward, it is determined in S800 that Y _R <Y _T is satisfied, and thereafter, in S900, a process of applying a braking force to one of the front wheels 18 and 22 corresponding to the inner wheel in the turning direction is executed. .

In this case, even when the vehicle is moving backward,
The braking force is generated on the wheels that can most efficiently eliminate the oversteer characteristic or the understeer characteristic, and as a result, a superior vehicle posture is ensured when reversing, as compared to the case where constant braking control is executed regardless of the traveling direction. It becomes possible to do.

As described above, the braking control device of this embodiment is
Wheels that can switch the control contents to be applied to the individual brakes 20, 24, 30, 34 depending on whether the vehicle is moving forward or backward and always ensure an optimum effect in relation to the traveling direction of the vehicle. The braking control is executed for. Therefore, even when the vehicle is moving backward, the target vehicle behavior can be accurately obtained as in the case of moving forward.

In the above embodiment, when the vehicle is moving backward, the control applied to the brakes 20, 24, 30, 34 when the vehicle is moving forward is performed with the front and rear wheels reversed, but the invention is not limited to this. In order to obtain a desired effect with a simpler control content, no braking control may be performed when the vehicle moves backward. In this case, it is possible to enjoy the effect of eliminating the unnaturalness as compared with the conventional device that executes inappropriate braking control when the vehicle moves backward.

The braking control system shown in FIG. 2 supplies the brake oil pressure generated in the master cylinder 14 to the brakes 20, 24, 30, 34 via the P valve 36. Therefore, as long as no abnormality occurs in the hydraulic system of the brakes, the front wheels 1 are attached to the brakes 30 and 34 of the rear wheels 28 and 32.
The brake hydraulic pressure is lower than that of the brakes 20 and 24 of 8 and 22.

As described above, the setting of the brake hydraulic pressure is effective when the vehicle is moving forward, but it is rather an obstacle to maintaining a stable vehicle posture when the vehicle is moving backward. Rear wheel 2 that increases the load during reverse braking
A large brake hydraulic pressure is supplied to the brakes 20, 24 of the front wheels 18, 22 from which the load is reduced by the brakes 30, 34 of the 8, 32 brakes.
This is because 8, 22 are in a state of being easily locked.

FIG. 9 shows a flowchart of a braking force correction routine executed by the main control device 96 in order to eliminate such an adverse effect caused by disposing the P valve 36. S1000
Is a step of determining whether or not the vehicle is moving backward similarly to S100 shown in FIG. If it is determined that the vehicle is not moving backward, there is no need to make any correction, and the current process is terminated.

On the other hand, if it is determined in S1000 that the vehicle is moving backward, the process proceeds to S1100 to read the output signal of the pedal effort sensor 11 for detecting the pedal effort of the brake pedal 10. Then, in S1200, the pedaling force sensor 1
An appropriate braking force to be generated on the rear wheels is calculated based on the output signal of 1, and the cylinder cut valve 41, the accumulator cut valve 63, and the hydraulic pressure control valves 43 and 45 are appropriately adjusted to secure the braking force. By controlling, the braking force addition processing is realized, and the processing of this time is ended.

In this case, although the brake oil pressure supplied from the master cylinder 14 to the main liquid passage 26 is lower than the brake oil pressure supplied to the main liquid passage 16 by the action of the P valve 36, when the vehicle is retreating. , The brake oil pressure exceeding the brake oil pressure supplied into the main liquid passage 16 is applied to the rear wheel 2
8, 32 brakes 30, 34 can be supplied. Therefore, ideal hydraulic pressure distribution at the time of reverse is realized, and a stable vehicle posture can be maintained.

The routine shown in FIG. 9 may be executed simultaneously with the braking control routine shown in FIG. 6 or may be executed independently.

By the way, the braking control system of this embodiment is
A cylinder cut valve 40 that constitutes a BS actuator,
41, the hydraulic control valves 42 to 45, the accumulator cut valves 62 and 63, etc. are controlled to execute the braking control for the purpose of achieving the target yaw rate Y _T. When 28 and 32 are locked, the ABS function operates to release the locked state and maintain a stable braking posture.

For example, when the left front wheel 18 is locked as a result of supplying hydraulic pressure from the master cylinder 14 to each wheel, the hydraulic pressure control valve 42 is switched to supply the brake hydraulic pressure supplied to the brake 20 to the reservoir 48. The process of releasing is performed. In this case, the braking force generated by the brake 20 is reduced, and the locked state of the left front wheel 18 is released.

When such processing is executed to exert the function as the ABS, generally, the front and rear wheels 18 and 22 are independently controlled for brake hydraulic pressure. This is to ensure the braking force efficiently. On the other hand, regarding the rear wheels 28 and 32,
From the viewpoint of securing the braking force and stabilizing the vehicle attitude, the same brake hydraulic pressure control is performed by the low select control so that the left and right wheels are not locked together.

However, the front and rear wheel brakes 20, 24, 3
The control of 0 and 34 as described above is based on the premise that the vehicle is moving forward. Originally, the left and right wheels located in front of the traveling direction are independently located in the rear of the traveling direction. The left and right wheels should be controlled identically.

Therefore, in the braking control device of this embodiment, in order to exert the function as the ABS, the front two wheels 18 and 22 are independently controlled and the rear two wheels 28 and 32 are controlled to the same when moving forward, and the front wheel when moving backward. Two wheels 18, 22 are the same, two rear wheels 2
It is supposed that 8 and 32 are controlled independently. For this reason,
In the braking control device of the present embodiment, it is possible to maintain a stable vehicle attitude during ABS operation not only when moving forward but also when moving backward.

When performing this processing, the rotation sensors 84, 86, 8 corresponding to the vehicle speed detecting means M1 described above.
Based on the detection results of Nos. 8 and 90 and the detection result of the steering angle sensor 80 corresponding to the above-mentioned steering angle detection means M2, the main controller 96 determines the appropriate wheel speed for each wheel 18, 22, 28, 32. The step of calculating constitutes the above-mentioned target behavior setting means M3.

The above-mentioned behavior detecting means M4 is also used by the rotation sensors 84, 86, 88, 90, and the main controller 96 determines the detection result of the rotation sensors 84, 86, 88, 90 and the proper wheel speed. As a result of comparison, the cylinder cut valve 4 detects the locked state of the wheels and releases the locked state.
By controlling the hydraulic pressure control valves 0, 41, the hydraulic pressure control valves 42 to 45, and the accumulator cut valves 62, 63, the braking control means M7 described above is realized.

[0077]

As described above, according to the present invention, the brake mechanism provided on the front wheels and the brake mechanism provided on the rear wheels are applied when the vehicle is moving forward and when the vehicle is moving backward. Braking control is reversed. For this reason, when the braking control is performed, the braking force generated on each wheel is always constant in relation to the traveling direction, and the same behavior change is obtained regardless of whether the vehicle is moving forward or backward. Can be generated.

As described above, according to the braking control device of the present invention, the target behavior can be ensured not only when the vehicle is moving forward but also when the vehicle is moving backward, and the stable vehicle posture is maintained. It has the feature that it can be secured.

[Brief description of drawings]

FIG. 1 is a principle configuration diagram of a braking control device according to the present invention.

FIG. 2 is an overall configuration diagram of a braking control device that is an embodiment of the present invention.

FIG. 3 is a diagram (part 1) showing a relationship between a braking force and a yaw rate.

FIG. 4 is a diagram (part 2) showing the relationship between braking force and yaw rate.

FIG. 5 is a diagram (part 2) showing the relationship between the braking force and the yaw rate.

FIG. 6 is a flowchart of an example of a braking control routine executed by the main controller of the present embodiment.

FIG. 7 is a flowchart of an example of a reverse movement determination routine executed by the main controller of the present embodiment.

FIG. 8 is a flowchart of an example of a yaw rate calculation routine executed by the main controller of the present embodiment.

FIG. 9 is a flowchart of an example of a braking force correction routine executed by the main controller of the present embodiment.

[Explanation of symbols]

 M1 Vehicle speed detecting means M2 Steering angle detecting means M3 Target behavior setting means M4 Behavior detecting means M5 Brake mechanism M6 Reverse determination means M7 Braking control means 18 Left front wheel 22 Right front wheel 28 Left rear wheel 32 Right rear wheel 20, 24, 30, 34 Brake 80 Steering angle sensor 83 Pedal switch 84,86,88,90 Rotation sensor 91 Yaw rate sensor 92 Front / rear G sensor 93 Shift position sensor 94 Ground vehicle speed sensor 96 Main controller

 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Masa Masa Chiba, Toyota City, Aichi Prefecture, Toyota Town, Toyota Motor Co., Ltd. (72) Inventor, Satoru Niwa 1, Toyota City, Aichi Prefecture, Toyota Town, Toyota Motor Co., Ltd. ( 72) Inventor Masafumi Ota 1 Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Corporation (72) Inventor, Akira Nakamura, 1 Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Corporation

Claims (1)

[Claims] 1. A setting result of target behavior setting means for setting a target behavior of a vehicle based on a vehicle speed detected by a vehicle speed detecting means and a steering angle detected by a steering angle detecting means, and an actual vehicle behavior. In the braking control device that appropriately controls the brake mechanism provided for each wheel so that the detection result of the behavior detection means that detects A braking control characterized by having a braking control means for switching the control applied to the braking mechanism of the front wheels and the braking mechanism of the rear wheels to execute the braking control depending on the result when the vehicle is moving forward and when the vehicle is moving backward. apparatus.